[Intel-gfx] [PATCH] drm/i915/cnl: Wa to ignore VBT alternate pin on B-stepping.

[Rodrigo Vivi]

Current VBT available for pre-production machines
tells that we need to use alternate pin. But if we use it
we end up needing to define a different table.

However if we respect the spec, ignore the VBT for now
we get a more reliable HDMI.

Cc: Clint Taylor <clinton.a.taylor at intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/i915/intel_hdmi.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index f8c40ae..0d389bc 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1884,7 +1884,8 @@ static u8 intel_hdmi_ddc_pin(struct drm_i915_private *dev_priv,
 		&dev_priv->vbt.ddi_port_info[port];
 	u8 ddc_pin;
 
-	if (info->alternate_ddc_pin) {
+	if (info->alternate_ddc_pin &&
+	    !IS_CNL_REVID(dev_priv, CNL_REVID_B0, CNL_REVID_B0)) {
 		DRM_DEBUG_KMS("Using DDC pin 0x%x for port %c (VBT)\n",
 			      info->alternate_ddc_pin, port_name(port));
 		return info->alternate_ddc_pin;
-- 
1.9.1